The cold side leathers were a bit rough, but the hot side leathers were crumbling. I got some new leathers from Don Worely, and will replace them when I reassemble. I've been in the gas engine hobby for many a long year, but this is one of the dirtiest, grimiest jobs I've encountered since my early days.
I am also going to clean up the regenerator, as well as the cylinders. The cold side had enough rust and grime at the bottom that it caused the piston to bottom out. Here are the soot covered regenerator plates. Thus one of the mysteries of the Rider engines is exposed.
Woody, Now that there are pictures to go by for the "look" of the piece and the fact that you have the engine on-hand, I will recommend making the piece you need of pine plank pieces. The old pattern makers did the same thing when it was new; why not do it again? You can fit the piece to your engine being sure to leave a 1/16" or so for shrink on one end (top to bottom for shrink is negligible here). Get the pattern just right for your engine and send to the Tomahawk Foundry in Rice Lake Wisconsin for the pattern to be cast in iron. Cheap to do and it will be perfect for your engine when it comes back or it will need VERY MINOR fitting. Don't feel as if you have to carve one by hand, all of the old patterns are "built up" from stock and the door you need is very easy to make in sections and glue together to form the pattern. Lightly sand the corners to replicate the round edges and send it off! Gorilla WOOD glue is best to use to put the pieces together; do not use regular gorilla glue as it foams. The phone number at the foundry is 715-234-4498 and you can speak with Allan for pricing. This is the way to go for such a rare piece, and it will cost less to make one than buy an original and you get the satisfaction of having made it yourself. It wont hurt to dig around where the engine sank into the floor in the flood as well. The old door is probably in the mud where it fell off when it flooded/sank. This is an easy pattern to make and you do not have to be a wood worker to do this job; table saw/ chop saw and palm sander only. If I can help, private message me or email firstname.lastname@example.org Good luck!
I got the leathers installed this Saturday. Earlier, I punched the bolt patterns into the leathers, and put the donut shaped pieces of 1/8" leather in plastic bags with some neat's foot oil for a couple of weeks. I also cleaned up both pistons, cylinders, and leather holders. Everything was in good shape. I only had to get some brown varnish off the machined surfaces of the pistons and polish with Scotch Brite.
I placed the hot piston first, since lifting the cold piston high enough by myself is a difficult and dicey operation. After several trims of the hot piston bottom leather, I got it to go in without jamming. I then used the top part to cut the bottom leather for the cold piston, so it would fit the first time. Mission: success. Got the top leathers installed and trimmed, just have to replace the crankshaft.